The proposed studies will lead to the production of a panel of monoclonal mouse and human melanoma antigen epitope specific antibodies. Antigens with which these antibodies react will be isolated and characterized. Studies will provide information on antigenic changes which accompany tumor progression. The clonal nature (or otherwise) of metastatic tumors will be established. The antigenic relationships of benign, premalignant and malignant human melanotic tissues will be examined and the role of the human immune response to melanoma antigens will be defined. Monoclonal tumor specific antibodies provide an unparalleled opportunity to study the antigens and immune responses to human melanoma and will allow the development of a rational approach to human tumor diagnosis and immunotherapy.